Alan Johnson completes Miliband's shadow cabinet.
Johnson was a surprise choice, The Independent reported. He supported Miliband's brother, former Foreign Secretary David Miliband in the leadership race.
The top contenders for shadow chancellor were believed to be Ed Balls, a former member of the Cabinet who ran for the party leadership, or his wife, Yvette Cooper, the first woman to serve as Chief Secretary of the Treasury.
Johnson supports keeping the goal set by former Prime Minister Gordon Brown of cutting the British budget deficit in half in four years. Balls suggested the pace should slow because of the economic slump.
A former general secretary of the Communication Workers Union, Johnson held several cabinet posts under Brown and former Prime Minister Tony Blair, most recently serving as home secretary.
Conservatives suggested the 60-year-old would be a short-term member of the shadow cabinet, functioning essentially as a place-holder.